Flexible abrasive brush



Sept 13, 1956 E. R. LINDENBORG 2,763,104

FLEXIBLE ABRASIVE BRUSH Filed July 19, ,1952 2 Sheets-Sheet 1 1N VEN TOR. EK/c' 7?. (war/v60.

Sept. 18, 1956 Filed July 19. 1952 2 Sheets-Sheet 2 INVENTOR. fx/c' K Z/NDf/VJORG.

FLEXIBLE ABRA'SIVE BRUSH Eric R. 'Lindenhorg, Indianapoiis, Ind, assigncr, by rhesus assignments, to Anton Vonnegut, Indianapons, ind.

Application duly '19, 1952, Serial No. 299,841;

3 Ciaims. (Cl. 51-196) This invention relates generally to an abrasive device and more particularly to a flexible abrasive brush adapted to be utilized for polishing, deburring or cleaning curved and contoured, internal surfaces.

In accordance with conventional polishing or deburring practices the internal surfaces of relatively small tubular devices have been deburred, cleaned and polished by applying a rotating wire brush. A brush of this type, when made with wire bristles, may develop scratching action to the workpiece as contrasted with an abrasive action whereby wire brushes can not be utilized where scratches on the finished piece would be objectionable. The wire brush may be used on internal surfaces of tubular structures provided that the diameter of the brush is approximately equal to the internal diameter of the tube, whereby it is necessary to provide for a plurality of brushes of diiferent diameters for treating the internal surfaces of tubes of different diameters. The Wire brush lacks lateral flexibility whereby it is not applicable to curved tubes or pipe elbows. The wire brush also lacks flexibility in that it does not operate efiiciently with respect to internal surfaces having threads, ribs, grooves or other types of internal surfaces in the form of concave curves. For example, the wire brush must be made up of wires having sufiicient stiffness to function properly and in order to have this stiffness the wires lack the flexi- 1 bility to contact all parts of internal surfaces with varying diameters as prevails with shoulders, threads, ribs or grooves.

More flexibility is obtained in a brush with Tampico or other fiber bristles than with a wire brush. The flexibility is needed for irregularly shaped orifices and for va ing diameters within the same hole, but the increased flexibility aiso accounts for a proportionate decrease in the abrading action of such a brush. The abrading action can be improved by applying abrasive grain after dipping the brush in oil, grease or other binding medium, but except for extremely fine polishing operations this method is quite inefiicient due to the rapid loss of abrasive and frequency with which it must be replenished.

Another device for deburring, cleaning and polishing internal surfaces consists of one or more strands or strips of sandpaper or abrasive coated cloth wrapped around the end of wooden or metal rod and held midway of the length of the strip, or strips, in a longitudinal slot at that end of the rod while the other end is attached to and rotated by a power tool. The centrifugal force of rotation keeps the ends of abrasive strips in contact with the internal surface and the device has more efficient abrasive action than wire or fiber brushes, but because the centrifugal action tends to unwrap the abrasive strips, the device usually must be inserted into the opening which is to be cleaned or polished before the power is applied, and its operation also is fairly well limited to uniform diameters of straight tubular sections.

Accordingly, the principal object of this invention is to provide abrasive apparatus for deburring, polishing or cleaning the internal surfaces of irregularly shaped ori- "atent fices as well as a tubular structure including surfaces such as those presented by threaded ribbed or grooved internal surfaces.

Another object of this invention is to provide a flexible abrasive device which is especially adapted to polish, deburr or clean the internal surfaces of curved tubular structures such for example as pipe elbows.

Stiil another object of this invention is to provide an abrasive device of flexible character with respect to its diameter whereby a given size of device may be utilized for polishing, deburring or cleaning internal surfaces of difierent diameters whereby it can be utilized to treat tapered holes or. holes having progressively different diameters with shoulders.

Still another object of this invention is to provide apparatus adapted to polish, deburr or clean external surfaces having concave or angular contours such as those formed by two adjoining members of a structure.

In accordance with this invention there is provided a brush having bristle-like abrasive members.

Further in accordance with this invention there is provided a brush with a central stem of twisted wires serving the two-fold purpose of holding one or more sheets of abrasive coated materials in a spiral arrangement around the stem and of supplying a means for rotating the assembly.

he full nature of the invention will be understood from the accompanying drawings and the following descrip tion and claims:

Fig. l is a front elevational view of a flexible abrasive brush constructed in accordance with this invention.

2 is an end view of the abrasive brush illustrated in Fig. 1 taken from the ieft hand end thereof.

Fig. 3 is a cross sectional view illustrating a modification of this invention having a single sheet of abrasive material.

Fig. 4 is a cross sectional view illustrating another modification of this invention comprising a folded abrasive sheet.

Fig. 5 is a cross sectional view illustrating another modification of this invention comprising three folded abrasive sheets.

Fig. 6 is a cross sectional view illustrating still another modification of this invention consisting of a single sheet of abrasive material having four folds therein.

Fig. 7 illustrates a sheet of abrasive material in flat form which has been prepared for application to the modification of the invention illustrated in Fig. 4.

Fig. 8 is a side eievational view of another modification of this invention comprising an accordion pleated abrasive sheet.

Fig. 9 is a detailed view illustrating the arrangement of the sheet illustrated in Fig. 8 with respect to the wire supporting mechanism.

Fig. 10 is a perspective view illustrating another modification of this invention.

Referring to Figs. 1, 2, 4 and 7 of the drawings there is provided in accordance with this invention a flexible abrasive coated cloth which is shredded to provide individual abrasive strips 11 at the ends thereof. The sheet may be so shredded as to provide uncut strips or bars 12. Thus, a shredded abrasive sheet is formed which may be folded in half as at 14 to form a folded sheet having the arrangement illustrated in Fig. 4. For supporting the abrasive sheet and forming it into a spiral abrasive brush as illustrated in Figs. 1 and 2, there is provided a Wire member 15 which may comprise either two wires 16, 17 or a single wire initially bent to form two parallel supporting members 16 and 17. The folded sheet 14 may be placed between the two adjacent wire members whereby they may be twisted to hold the abrasive sheet in the spiral formation shown in Figs. 1

and 2. Member 15 may also comprise a shank portion 18 adapted to be held in a chuck for rotation.

One or more sheets 14 can be twisted into spiral arrangement between a pair or a multiple number of wires and for convenience in the manufacture of this device a double width of sheet can be folded with the abrasive side of the sheet exposed instead of using two separate sheets back to back, provided the parallel slashes are continued through the folded edge as well as through the two free ends of the sheet. Two or more such double sheets can be grouped into a single unit and twisted into a spiral arrangement between two centrally disposed wires. With a group of three or more double sheets it is well to use three or more wires to obtain a more uniform spirally arranged distribution of the shredded ends, and thereby develop a structure quite similar to that of a fiber brush. The same effect is obtained by using a relatively long single sheet of abrasive and folding it back and forth upon itself, and twisting it into a spiral arrangement between a multiple number of wires as shown in Fig. 6.

The spiral structure of the abrasive sheet forms a generally cylindrical brush member, the bristle-like members and 11 of which have abrasive surfaces. If desired, the sheet may be coated with abrasive material on one side only, or both sides of the sheet may be coated for providing bristle-like members which present an abrasive surface regardless of the direction of rotation of the brush.

The brush may be chucked in any suitable driving mechanism and applied to the internal surfaces of a tubular member and rotated at relatively high speed, preferably between five and fifteen thousand R. P. M. The abrasive bristles are forced by centrifugal force into grinding contact with the internal surfaces regardless of their contour. Because of the abrasive action, these internal surfaces are deburred, polished and cleaned regardless of the configuration of the particular surface. The bristles may be of any desired width from A of an inch to one inch, depending upon the nature of the surface being polished. For example, a screw thread would require a relatively narrow bristle whereas a plain surface with or without a shoulder would probably require a relatively wide bristle. A brush of this type may be used within a tube having substantially the same diameter as the brush or a diameter down to less than 50% of the outer diameter of the brush. It is preferable, however, that a brush having a diameter of the order of six inches be used to polish a tube having an internal diameter of the order of five inches. This proportion may be taken as typical for tools of different diameters.

The intended use of a brush determines the diameter of the wires forming member and the number of twists per inch. If a brush is to be used in a straight tube, the wire size may be relatively large to provide sufficient stiffness to prevent off-center rotation. Also the number of twists per inch may be relatively high. Alternatively, a brush for use in curved tubular structures should comprise relatively small wires having a smaller number of turns per inch.

Figs. 3, 5, 6, 8 and 9 show other modifications of this invention. For example, Fig. 3 illustrates the use of a fiat sheet of abrasive material having shredded portions 30 and 31 joined together at the mid point thereof by means of a unitary band 32. In this modification of the invention, it is probably preferable that both sides of the abrasive sheet may be coated with an abrasive material. Fig. 5 illustrates the use of three separate abrasive sheets 40, 4?. and 42 folded as illustrated in Fig. 4 and bound together by three strands 5t 51 and 52 of twisted wire. Fig. 6 illustrates the use of a single abrasive sheet 60 of material having four folds therein.

A sheet such as that shown in Fig. 7 would be provided with four attaching members 12 separated by three continuous shredded portions and having two outer shredded end portions. in this modification of the invention it is not necessary that both sides of the sheet be coated with abrasive material as a coated surface is presented to the work regardless of the direction of rotation of the brush.

Figs. 8 and 9 illustrate an unshredded sheet of abrasive material 54 which is initially accordion pleated, then laid between a pair of wires 16 and 17 and twisted to form a spiral brush member. This modification also requires a sheet coated on only one side with abrasive material.

The desired spiral arrangement cannot be attained with a plain and solid or continuous sheet of abrasive material. The attempt to form such a sheet into a spiral between twisted wires would result in a distorted tubular arrangement of the sheet in which both of its ends would be torn by a shearing action of the twisted wires, but the objective is readily obtained by folding the sheet into a series of closely spaced pleats running at right angles to the direction of the two centrally located wires. Twisting the wires will cause the sheet to form itself into a spiral arrangement around the wires with ruffled or serrated edges formed by adjacent sides of each pleat, thereby providing means for abrading action between threads, in grooves and in other depressed areas of internal surfaces.

Such a brush, made of a continuous pleated sheet has sufficient flexibility so that a given diameter of brush can be used for reasonable variations in diameters of internal areas, but it is relatively stiff and especially adapted for deburring and cleanup operations requiring considerable abrading action rather than for internal polishing operations.

Fig. 10 of the drawings illustrates an abrasive brush comprising a folded sheet metal handle member 55, a plurality of abrasive strips or bristles 55 and an abrasive retaining portion 57. The bristled members 56 may be formed by shredding a rectangular sheet of abrasive coated cloth or other material and a plurality of such sheets may be assembled and inserted between the lips of bristle retaining member 57. These lips may be bent toward one another into compressive relationship to the abrasive material thereby to provide a firm support for this material. This type of brush may be utilized for deburring, cleaning and polishing fiat interior surfaces within a tube, or it may be utilized for performing the same operations on the exterior surfaces of metallic or wood products. A brush of this type is especially adapted to deburr, polish or clean surfaces having irregularities such as threads or shoulders.

From the foregoing description of this invention it will be apparent that the abrasive brush is adapted to polish, deburr or clean internal surfaces of almost any conceivable configuration. It is self-centering with respect to a tubular member as it would naturally seek a centered position due to the effects of centrifugal force on the individual bristle members. The outer ends of the bristles take the major portion of wear when the brush is applied in accordance with the preferred meth- 0d, and, therefore, it naturally wears to smaller and smaller diameters and can be used on tubular surfaces of smaller and smaller diameters as the wear progresses.

While this invention has been described as particularly applicable to the internal surfaces of tubular structures, it will be readily understandable that this invention is equally applicable to internal surfaces regardless of their contour so that internal surfaces may be deburred, polished or cleaned whether they be tapered, shouldered or include threads, ribs or grooves. It will be equally understandable that the invention may also be applied to contoured external surfaces having concave curves and inclusive angles such as those between adjoining members of various structures.

Other modifications of this invention may include a multiple number of sheets in place of the single sheet such as that shown in Fig. 3, the multiple number of sheets being held between a pair of wires as illustrated in Fig. 3. The invention may also be modified by providing a greater number of loops of abrasive material with a proportionately greater number of wire strands. In this case the wire strands may be of relatively smaller diameter, thus facilitating the twisting of the larger number of wires both upon themselves and upon the greater mass of coated abrasive material. A greater number of smaller wires also supplies the structural strength equal to that of a smaller number of larger diameter wires. It is to be noted that the provision of the looped or folded ends 14 contributes to greater convenience and economy of manufacturing an abrasive brush from continuous strips of abrasive material 10 than would prevail with the use of a larger number of shorter pieces of coated abrasive material. It should also be noted that the various modifications of this invention may comprise abrasive sheets coated with abrasive on one or both sides of the sheet, as will be determined by the particular application of the brush.

The invention claimed is:

1. An abrasive brush comprising a stem formed of a number of twisted wires and an abrasive sheet disposed between said wires and folded in a series of pleats, said wires holding said sheet in a spiral form with the pleats extending transversely of said wires to permit twisting distortion of said sheet.

2. An abrasive brush comprising a stem and an abrasive sheet folded in a series of pleats, said stem holding 30 said sheet in a spiral form with the pleats extending transversely of said stem to permit twisting distortion of said sheet.

3. An abrasive brush comprising a stem and an abrasive sheet supported on said stem and folded in a series of pleats.

References Cited in the file of this patent UNITED STATES PATENTS 624,160 Black May 2, 1899 963,523 Crismore July 5, 1910 1,195,190 Dunlap Aug. 22, 1916 1,460,850 Hokanson July 3, 1923 2,015,030 Collier Sept. 17, 1935 2,049,324 Schneider July 28, 1936 2,230,968 Cave Feb. 4, 1941 2,328,998 Radford Sept. 7, 1943 2,388,867 Peterson Nov. 13, 1945 2,465,396 Peterson et al Mar. 29, 1949 2,609,642 Peterson Sept. 9, 1952 FOREIGN PATENTS 13,962 Germany Sept. 14, 1880 306,713 Great Britain Feb. 28, 1928 OTHER REFERENCES Grits and Grinds, volume 33, No. 4, page 9, April 1942; published by Norton Company, Worcester, Massachusetts. 

